Video 4-34. Percutaneous purse-string suture
As with the buried purse-string closure, this technique is designed to use circumferential tissue advancement to either shrink the size of a defect or obviate it entirely, depending on the degree of tension and the size of the defect. It is a niche technique, since the purse-string effect tends to lead to a slight puckering in the surrounding skin, a feature that may be acceptable (and will likely resolve with time) on areas such as the forearms and back but is less desirable in cosmetically sensitive locations such as the face. The running nature of the technique means that compromise at any point in the course of suture placement may result in wound dehiscence, though for this reason, a larger gauge suture material is generally utilized. This percutaneous approach is most useful either for relatively narrow wounds or those with marked atrophy of the surrounding skin, such as on the shins and scalp.
Suture choice is dependent in large part on location, though as always, the smallest gauge suture material appropriate for the anatomic location should be utilized. On the extremities and scalp, where this technique is generally used, a 3-0 or 4-0 absorbable suture material may be used. On the back and shoulders, 2-0 or 3-0 suture material is effective. Since the technique requires easy pull through of suture material, monofilament absorbable suture is generally preferable.
At the wound edge at the far end of the round- or oval-shaped wound, the needle is inserted at 90 degrees through the epidermis parallel to the incision line 5-20 mm set back from the wound edge. Alternatively, if absorbable suture material is used, the needle may enter from the underside of the dermis so that the final knot will be buried.
The curvature of the needle is followed keeping the same distance from the wound edge so that the needle exits through the epidermis 10-15 mm to the left of the entry point at the same distance set back from the wound edge by following a trajectory running parallel to the incision. Bite size is dependent on needle size. The needle should exit the dermis at a point equidistant from the cut edge from where it entered.
The needle is then grasped with the surgical pickups and simultaneously released by the hand holding the needle driver. As the needle is freed from the tissue with the pickups, the needle is grasped again by the needle driver in an appropriate position to repeat steps (1) through (3). With each throw, however, the needle pierces the epidermis through the exit hole of the prior throw.
A small amount of suture material is pulled through with each throw.
The same technique is repeated ...